Heterocycles derived from dichlorothiophene

A number of new, air-stable heterocycles have been synthesized which contain 2,5-dichlorothiophene groups as the structure-forming units with sulphur, selenium, tellurium, phosphorus, arsenic, antimony, bismuth, tin and mercury acting as the hetero-atoms.     

Uranium(IV) polyoxotungstophosphates

Two tris(oxouranium)-substituted Keggin and Dawson sandwich-type tungstophosphate heteropolyanions Na₁₂[(UO)₃(H₂O)₆(PW₉O₃₄)₂]·21 H₂O (1) and Na₁₈[(UO)₃(H₂O)₆(P₂W₁₅O₅₆)₂]·27 H₂O (2) have been prepared by reaction of uranium sulphate with [PW₉O₃₄]⁹⁻ and [P₂W₁₅O₅₆]¹²⁻, respectively, in aqueous media at 4.7 pH. The products were characterized by elemental and thermal analyses, IR, UV-Vis spectroscopy and magnetical susceptibility. The results of these studies suggest that the compounds obtained from Keggin and Dawson trilacunary anions are 2∶3 sandwich-type complexes and both exhibit a square antiprismatic stereochemistry for uranium(IV) with retention of polyoxometallate parent structure.     

Gated and Differently Functionalized (New) Porous Capsules Direct Encapsulates' Structures: Higher and Lower Density Water

Either more or less neighbors favored? By deliberate choice of the internal ligands of the porous nanocapsules [{(Mo)Mo₅}₁₂{Mo₂(ligand)}₃₀]^n?, the respective cavities can be differently sized/functionalized. This allows one to trap, in two different corresponding capsules, 100 water molecules arranged in shells that exhibit more and less dense packing, respectively—the latter type in a capsule with smaller internal ligands; the picture shows the related 100 O atoms at the vertices of the four polyhedra, while two dodecahedra (shown in pale green and red) have only 10 H₂O molecules instead of 20.

     

Oxo-Centered Trinuclear Chromium(III) Complexes with Both Carboxylate and Amidoximate Ligands

Compounds [Cr ₃ ^III (μ₃-O)(O₂CPh)₅(H₂N-sao)(EtOH)₂]·EtOH (1·EtOH) and [Cr ₃ ^III (μ₃-O)(O₂CPh)₃(H₂N-pao)₃]NO₃·H₂N-paoH·EtOH (2·NO₃·H₂N-paoH·EtOH) have been obtained either in a sequential one-pot, two-step procedure in which Cr(NO₃)₃·9H₂O is first reacted with sodium benzoate in ethanol under reflux, followed by the addition of salicylamidoxime (H₂N-saoH₂) or pyridine-2-amidoxime (H₂N-paoH), or in a one-step protocol starting from [Cr ₃ ^III (μ₃-O)(O₂CPh)₆(EtOH)₃]NO₃. They were characterized by single-crystal X-ray diffraction, magnetometry and EPR spectroscopy. Complexes 1 and 2 are derived from the parent complex [Cr ₃ ^III (μ₃-O)(O₂CPh)₆(EtOH)₃]⁺ by replacement of one and three benzoate ligands, respectively, by oximate ligands. The salicylamidoximate and pyridine-2-amidoximate ligands display a tridentate coordination mode with the N–O oximate group bridging a pair of Cr atoms and the additional ligating atom substituting for an ethanol ligand of the parent complex. In both cases susceptibility, magnetization and EPR data reveal a S _T = 1/2 ground state with a nearly isotropic g-tensor.